The subject of this research project is the investigation of the mechanism by which glucocorticoids affect cholesterol biosynthesis in established human cell lines of neoplastic derivation. The investigation is focused on differences in the response to glucocorticoids between the substratum-adherent epithelioid cells and the suspension-grown lymphoid cells. The specific areas selected for investigation include: 1. Study of the time-course effects of C21 steroids on DNA synthesis and cholesterol synthesis in lipid-depleted cells by means of flow fluorometry. 2. Selection of steroid-resistant variants for the purpose of comparing their biosynthetic activity leading to the formation of mevalonate. 3. Establishing possible connection between the demonstrated accumulation of surface glycoproteins and mevalonate through studies of steroid effects on dolichol synthesis. 4. Analysis of changes in the distribution of phospholipids in cells treated with glucocorticoids in the absence of exogenous sources of lipids.